The present invention relates to an alarm actuating roller shutter. In particular, the invention relates to a roller shutter in which the alarm is actuated by a magnetic switch.
The subsequent installation of roller shutters into preexisting window structures creates specific problems because the preexisting window structure precludes the possibility of building into the window structure protective devices such as special switches in the window sill. In subsequently installed roller shutters, the problem of accommodating the safety element such as a release switch for an alarm system in the frame of the roller shutter arises. Here difficulties are caused by the limited space available for the installation of such protective switches.
Various protective devices designed to actuate an alarm during an unauthorized lifting of a closed roller shutter are known. These devices generally are mechanical devices in which the switch consists of a contactor arranged laterally on the armor inside a guide rail cross section of a guide rail, and a stationary switch which is mechanically switched by the contactor in the closed position of the armor. Generally the stationary switch is not visible from the front installation side (side furthest from window) of the roller shutter.
Frequently, roller shutters provided with these conventional devices suffer a drawback in that improper functioning of the mechanically interlocking switches either leads to a complete failure of the desired protective action, or to blocking of the armor or of the winding roller with the roller shutter closed due to engagement of the switches. In addition, the mechanical release of these switches necessarily causes wear of the switching elements. This wear can result in failure of the switches themselves after a prolonged installation time and frequent use, particularly with the access of dust and dirt which can never be completely prevented. In winter the switches of these roller shutters may actually freeze and become inoperable.
Accordingly, it is an object of the present invention to provide a roller shutter in which the proper functioning of the protective switch is ensured even under the above mentioned unfavorable conditions.
It is a further object of the present invention to provide a roller shutter of simple design.